Description
In the Linux kernel, the following vulnerability has been resolved: net/smc: fix LGR and link use-after-free issue We encountered a LGR/link use-after-free issue, which manifested as the LGR/link refcnt reaching 0 early and entering the clear process, making resource access unsafe. refcount_t: addition on 0; use-after-free. WARNING: CPU: 14 PID: 107447 at lib/refcount.c:25 refcount_warn_saturate+0x9c/0x140 Workqueue: events smc_lgr_terminate_work [smc] Call trace: refcount_warn_saturate+0x9c/0x140 __smc_lgr_terminate.part.45+0x2a8/0x370 [smc] smc_lgr_terminate_work+0x28/0x30 [smc] process_one_work+0x1b8/0x420 worker_thread+0x158/0x510 kthread+0x114/0x118 or refcount_t: underflow; use-after-free. WARNING: CPU: 6 PID: 93140 at lib/refcount.c:28 refcount_warn_saturate+0xf0/0x140 Workqueue: smc_hs_wq smc_listen_work [smc] Call trace: refcount_warn_saturate+0xf0/0x140 smcr_link_put+0x1cc/0x1d8 [smc] smc_conn_free+0x110/0x1b0 [smc] smc_conn_abort+0x50/0x60 [smc] smc_listen_find_device+0x75c/0x790 [smc] smc_listen_work+0x368/0x8a0 [smc] process_one_work+0x1b8/0x420 worker_thread+0x158/0x510 kthread+0x114/0x118 It is caused by repeated release of LGR/link refcnt. One suspect is that smc_conn_free() is called repeatedly because some smc_conn_free() from server listening path are not protected by sock lock. e.g. Calls under socklock | smc_listen_work ------------------------------------------------------- lock_sock(sk) | smc_conn_abort smc_conn_free | \- smc_conn_free \- smcr_link_put | \- smcr_link_put (duplicated) release_sock(sk) So here add sock lock protection in smc_listen_work() path, making it exclusive with other connection operations.
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
Linux Linux
Default version status: unaffected
3b2dec2603d5b06ad3af71c1164ca0b92df3d2a8 to < f502a88fdd415647a1f2dc45fac71b9c522a052baffected3b2dec2603d5b06ad3af71c1164ca0b92df3d2a8 to < 0cf598548a6c36d90681d53c6b77d52363f2f295affected3b2dec2603d5b06ad3af71c1164ca0b92df3d2a8 to < 673d606683ac70bc074ca6676b938bff18635226affected3b2dec2603d5b06ad3af71c1164ca0b92df3d2a8 to < 6f0ae06a234a78ae137064f2c89135ac078a00ebaffected3b2dec2603d5b06ad3af71c1164ca0b92df3d2a8 to < 2c7f14ed9c19ec0f149479d1c2842ec1f9bf76d7affected
Linux Linux
Default version status: affected
4.18affected0 to < 4.18unaffected5.15.174 to ≤ 5.15.*unaffected6.1.120 to ≤ 6.1.*unaffected6.6.66 to ≤ 6.6.*unaffected6.12.5 to ≤ 6.12.*unaffected6.13 to ≤ *unaffected
References
- https://git.kernel.org/stable/c/f502a88fdd415647a1f2dc45fac71b9c522a052b ↗
- https://git.kernel.org/stable/c/0cf598548a6c36d90681d53c6b77d52363f2f295 ↗
- https://git.kernel.org/stable/c/673d606683ac70bc074ca6676b938bff18635226 ↗
- https://git.kernel.org/stable/c/6f0ae06a234a78ae137064f2c89135ac078a00eb ↗
- https://git.kernel.org/stable/c/2c7f14ed9c19ec0f149479d1c2842ec1f9bf76d7 ↗
- https://lists.debian.org/debian-lts-announce/2025/03/msg00001.html ↗